The security of certificate is the basis of secure network communications between vehicles or apparatuses. In the new types of wireless networks, it is common to exchange messages directly between vehicles or apparatuses due to application purpose or efficiency. For example, within the vehicular safety communication applications promoted by European and American governments in recent years, vehicles are requested to exchange the positions, speeds, and statuses to each other directly every 100 milliseconds (ms). In such a short time, the vehicle communication unit cannot query and wait the response from a Certificate Authority (CA) before verifying exchanged message. Therefore, the vehicle communication unit cannot know whether the corresponding certificate of each message is legal. Currently, most of the existing certificate management architectures rely on the certificate revocation list broadcast by the certificate authority periodically.
When a user does not update the certificate revocation list regularly or the user cannot obtain the latest certificate revocation list immediately, the user may authenticate the message signed by a revoked certificate mistakenly, and then exchanges the messages or trades with it. The situation that the user does not update the certificate revocation list regularly may lead to the consequences for such as chaotic traffic conditions, transaction fraud, leakage of personal information and low reliability of systems for the public.
Thus there is a need to develop a method and system used in a CA for adjusting the frequency of updating a certificate revocation list.